1. Field of the Invention
The present invention relates to an electro-optical device using an electrochromic material having electrochromic phenomenon and an electro-optical light controlling device using an adhesive or tacky high polymer as an electrolyte capable of light-controlling a large area.
2. Description of the Prior Arts
Electro-optical devices utilizing the electrochromic phenomenon have been developed in practical applications for display devices (e.g., watches etc.) in view of their excellent contrast and as light controlling devices for automatically controlling incident sun light or artifical light in windows of buildings, vehicles, ships, and airplanes.
Heretofore, it has been known to prepare an electro-optical device which comprises an electrochromic material of WO.sub.3, MoO.sub.3, TiO.sub.2 or Ir.sub.2 O.sub.3 and an electrolyte layer containing an ion for coloring the electrochromic material which is held between a pair of electrodes. It has been mainly studied to apply the devices to small size displays.
Solid, liquid and semisolid electrolytes have been proposed as the electrolytes used in the devices. In large area usage requiring a satisfactory percent transmission modulation, these solid electrolytes cause slow response, have a narrow modulation range, and are in a form of multi coated layers with a low productivity. Moreover, it is difficult to give uniform characteristics in a large area. The use of liquid electrolytes for large areas cause difficulty in panel preparation and inhibition of leakage of the electrolyte.
It has been proposed to use a gel electrolyte as the semisolid electrolyte, in Japanese Patent Publication No. 43387/1979 wherein polyvinyl alcohol, polyacrylamide, ethyleneglycol, sodium silicate, silica gel and glycerine with sulfuric acid etc. are disclosed. However, this gel lacks tackiness whereby it is difficult to prepare a device having a large area. Moreover, there are difficulties of durability and handling since a high concentration of sulfuric acid is used.
The use of polystyrene, polyethylene, sulfonic acid and perfluorosulfonic acid are disclosed in G. B. Pat. No. 2,005,856, however, these also lack adhesiveness whereby it is difficult to prepare a large panel. The use of copolymers of a vinyl monomer and a comonomer are disclosed in G. B. Pat. No. 2,014,326, however, these electrolytes contain a high content of water whereby there are difficulties of adhesiveness and durability.